(16)
WPT (waypoint) switch - When the display selector switch
(13)
is set to WPT, selects waypoints 1 thru 9 for entry of waypoint coordinates and their presentation on left (2) and right (3) displays.
(17)
From/to waypoint display - Displays from and to waypoint number of track leg being navigated.
B. System Turn On
(1)
Set mode switch from OFF position. For approximately 5 seconds, a lamp test is executed and all indicators and displays should illuminate. This includes the TK CHG, ENT, HLD, and CLR pushbuttons.
(2)
After 5 seconds, only the ENT pushbutton will be on, annunciators will be off, and the left and right displays will show the system identification number, the computer program number, and the computer subprogram number from left to right.
C. Initialization
(1) Before the system will be ready for navigation after turn on, present position, GMT, and date must be entered. Present position is entered as follows.
NOTE: The ONS includes a data entry monitoring feature which will display an OE (operator error) on the right display when an erroneous entry is attempted. CLR must be pressed and the data re-entered.
(a)
Set display selector to POS.
(b)
Press N or S for north or south latitude.
(c)
Load present latitude starting with the most significant bit. Continuing entering position in degrees, minutes, and tenths of a minute. Left display should show entered latitude.
(d)
Press ENT pushbutton.
(e)
Press E or W for east or west longitude.
(f)
Load longitude in same manner as latitude and press ENT.
(2) GMT and date entry.
(a)
Set display selector to GMT DAT.
(b)
Press GMT pushbutton. Left display will blank.
Sep 20/81 34-59-01 Page 15
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(c)
Load GMT hours and minute starting with most significant bit.
(d)
Press ENT pushbutton. It will remain on.
(e)
Press DAT pushbutton. Right display will blank.
(f)
Load DAT in month-day-year sequence.
(g)
Press ENT pushbutton; it will go out.
(3) Waypoint entry
(a)
Set display selector switch to WPT and set WPT switch to 1.
(b)
Load waypoint coordinants in the same manner used to load present position.
(c)
Repeat procedure for waypoints 2 thru 9.
D. System Status
(1)
The display selector switch is placed into the DTK-STS position to obtain the system status code in the two right digits of the right display. The status starts at 90 at system turn on and decreases to 01 when navigation status is obtained.
(2)
Status 90: Self-test mode. All display segments, six annunciators, and TK CHG, ENT, HLD, and CLR pushbuttons are illuminated for five seconds. The RPU performs an antenna test. If the antenna test fails, the WRN annunciator will begin flashing. The system will remain in status 90 until present position has been entered.
(3)
Status 80: RPU not up to temperature. The system remains in status 80 for a minimum of 3 minutes to allow circuits to stabilize.
(4)
Status 60: Synchronization mode. When the RPU is up to temperature, it then begins to sample the received signals and identifies the signals by comparing them to their known transmission pattern. If synchronization is not completed within three minutes, the WRN annunciator will begin flashing.
(5)
Status 30: Station selection mode. The RPU will spend from 0.5 to 1.5 minutes monitoring and selecting stations for navigational use. The process of station selection continues as the ONS enters status 03 (dead reckoning) or status 01 (Omega navigation).
(6)
Status 04: Grid navigation mode
(7)
Status 03: Dead reckoning mode. The RPU monitos the Omega stations for proper and reliable signals and remains in the dead reckoning mode for up to 0.5 minutes before entering the navigate mode. Both GMT and the date must be entered and a proper station selection geometry must be acquired before the system will advance its status. Dead reckoning mode may also be entered, if the ONS is in the navigational mode and station quality deteriorates sufficiently.
(8)
Status 02: VLF NAV mode. The system will attain a status 02 when two Omega stations and at least one VLF station provide valid signals. If no VLF stations are available, the system will operate in the DR mode.
(9)
Status 01: Navigation mode
E. System Action/Malfunction Codes
(1) The red WRN annunciator comes on steady to indicate that the system has failed and is no longer operative. However, if the WRN annunciator comes on flashing the action/malfunction codes should be investigated to assist in fault identification.
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